| Document and Entity Information | Oct. 30, 2019 |
| Cover page. | |
| Pre-commencement Issuer Tender Offer | false |
| Pre-commencement Tender Offer | false |
| Soliciting Material | false |
| Written Communications | false |
| Document Type | 8-K |
| Document Period End Date | Oct. 30, 2019 |
| Entity File Number | 001-36257 |
| Entity Registrant Name | RETROPHIN, INC. |
| Entity Central Index Key | 0001438533 |
| Amendment Flag | false |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 27-4842691 |
| Entity Address, Address Line One | 3721 Valley Centre Drive |
| Entity Address, Address Line Two | Suite 200 |
| Entity Address, City or Town | San Deigo |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92130 |
| City Area Code | 888 |
| Local Phone Number | 969-7879 |
| Title of 12(b) Security | Common Stock, par value $0.0001 per share |
| Trading Symbol | RTRX |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
